Partial restoration of a Marantz 2270

cortico

This time sharing a partial restoration of a 2270. This old amps totality deserve being salvaged. Someone was in there before and did a few silly things as replacing just one of the filter caps, the unit was having issues that were resolved after project was complete.

The planed scope was done as follows:

Power supply
-Replace and upgrade mail filter caps, total capacitance was increased.
-Replace all electrolytic capacitors.
-Replace speaker protection relay, this has fixed right channel intermittence.
-Upgrade diodes with fast soft recovery diodes, this reduces background noise.
Used a Omron relay, Nichicon KG main filter and Elna Silmic II caps

Preamp
-Replace all electrolytic capacitors.
Used Elna Silmic II and Panasonic ECQ films, 3.3uf and lower can take film.

Power amp
-Replace all electrolytic and tantalum capacitors.

Phono Board
-Replaced 2SC458 transistors with KSC1845, originals have a tendency to become leaky and add noise.
-Replace all electrolytic and tantalum capacitors.
-Upgraded existing diodes

-New vellum paper
-New incandescent bulbs
-New power switch and safety cap

Before:


After:
Top

Bottom


Power supply:
Before:


After



These are huge:



Pre amp, access was somewhat difficult:
Before:


After:



Power amp, the access was also not easy:




Phono amp


Some of the part replaced:

mlistens03

Wow. I always have loved the look of vintage amplifiers. I think this one is especially pretty. Nice job!

cortico

Thanks mlistens0, They look good and they sounds very nice as well.

westmassguy

Very nice work!

mhardy6647

The 2270 was (is) a very special piece -- it would be interesting to hear (so to speak) how you think it compares to the 1060 amplifier you "did"!

cortico

westmassguy wrote: »

Very nice work!

Thank you westmassguy! It’s great to have a nice complement from a talented person!

mhardy6647 wrote: »

The 2270 was (is) a very special piece -- it would be interesting to hear (so to speak) how you think it compares to the 1060 amplifier you "did"!

mhardy6647, the Model 2270 is a beast in every sense, sounds more punchy, has a more coherent frequency response, has the Marantz vibe in it but is precise and sounds more dynamic.

Probably, I think it’s conservatly rated at 75w per channel, probably to much power for my listening space, It has to be fairly loud to sound its best. I can’t dial it in at low listening volumes.

Does it sound nuts if I pick the little 1060? I need to admit that I am very partial to the amp I just rebuilt, but to my hears, now sonically supersedes the 2270. It also seems to be a better fit to my speakers, room and listening level.

With that being said, I am fond of the capacitor output coupled designs’ typical sound “coloration” in the sound, I leaned that it’s a flaw present in a form of pleasent distortion that I perceive as a warm and velvety sound.

Conradicles

Fantastic job!!!

cortico

Thanks Conradicles!

It’s curious that Marantz lower end units as the Model 1060 shared the same pre amp as the TOTL:

Original 2270 pre amplifier board:


Rebuilt 1060 pre amplifier board:

Kingrat

It's common, more than you think to share modules within units of the same vintage, even with large price differences. Lots of old units I used to sell and too often, fix, back in the mid 70's had the same boards for the tuner, preamp/phono. The amp sections were where the big differences were, along with the PS and size/weight of the unit. The main problems back then were bad solder joints and heat cooking caps and sometimes ICs. The cooking of ICs seems to have made a comeback in some Denon and other similar HT receivers with the transformer partially covered by a board filled with temp sensitive parts. NOT a good idea.
This is a Marantz SR5012, and I don't see this ending well at all:
https://cdn3.volusion.com/exvfd.rdrcz/v/vspfiles/photos/SR-5012-5.jpg